During the startup, after scanning the system led's, the controller performs a series of self-diagnostic operations. When any faults are detected or the operator has to be informed of any given situation, the self-doagnosis procedure is temporarily interrupted, signalling the event.
The fault signal is made by led's L1, L2 and a message is given on display (if present).

n.	Led ON	System Message (if display present)	Description	Type
1	L1	System Data WRITE ERROR	Indicates that a write error has occurred during the configuration data saving.	B
2	L2	System Data IS RESTORED FROM DEFAULT	Indicates that the configuration data has been restores to the default settings.	C
3	L1 L2	System Data is updated Please verify new data	Indicates that the configuration data has been converted into a new format. Check that the previous settings have been maintained.	C
4	L3	Firmware is updated old: 1K31F10 1.001 new: 1K31F10 1.002	Indicates that a firmware update has been made.	C

When the condition detected allows to continue to the start stage (type C) and waits for the FUNC button to be pressed to continue the boot procedure.

The controller waits 5 seconds before continuing with the startup stage, without waiting for a button to be pressed.

When the situation does not allow to continue the startup stage (tipo B), the led err flashes continuously.